KR100879054B1 - Scanning color display apparatus which can control gamma, color image controlling method and recordable medium thereof - Google Patents

Abstract

Light source; A one-dimensional optical modulator device for generating a modulation beam of a one-dimensional scan line modulating the color light emitted from the light source; A scanner for projecting the modulated beam to a predetermined position on a screen; And receiving an image signal, and converting input light intensity information extracted from the image signal into converted reference light intensity information having a gamma variable adjusted and linearly reduced, and wherein the color light is a 1D optical modulator device according to the reference light intensity information. A scanning color display device may be provided that includes an image control circuit that is modulated to and projected onto the screen through the scanner. There is an effect of eliminating the unevenness of brightness in the vertical direction of the projected image generated without correction and improving the image quality.

Gamma, Scanning, Color Image, Reference Table, Luminance

Description

Scanning color display apparatus which can control gamma, color image controlling method and recordable medium

1 is a graph showing a relationship between light intensity versus driving voltage (V) and light intensity versus brightness in a general driving integrated circuit.

2 is a graph showing a relationship between light intensity versus driving voltage (V) and light intensity versus brightness in a driving integrated circuit having a linear characteristic.

3 is a block diagram of a scanning color display device including a one-dimensional optical modulator device according to an embodiment of the present invention.

4 to 6 is a view showing the micro mirror and modulation principle included in the one-dimensional optical modulator element.

7 is a flowchart of a color image control method according to an exemplary embodiment of the present invention.

8 is a flow chart of a method of forming a transform or lookup table for color image control in accordance with the present invention.

9 is a graph showing the relationship between the driving voltage (V), the displacement (H) and the brightness (I) of the micromirror 20 in the one-dimensional optical modulator element.

10 is a graph showing the relationship between input light intensity information (B _input ), displacement (H) and brightness (I) of a micromirror in a one-dimensional optical modulator element before correction.

FIG. 11 is a graph illustrating a conversion relationship reflecting a gamma variable between input light intensity information and reference light intensity information according to an exemplary embodiment of the present invention. FIG.

12 is a view showing the brightness curve of the modulation beam compared to the input light intensity information according to the present invention.

<Description of the symbols for the main parts of the drawings>

110: light source

130: 1-D optical modulator element

150: scanner

170: screen

180: image control circuit

20: micro mirror

The present invention relates to a scanning color display device, and more particularly, to a scanning color display device and a method thereof, in which a gamma parameter can be adjusted by digitally preprocessing a driving integrated circuit included in a one-dimensional diffractive optical modulator device. will be.

Recently, with the development of display technology, the demand for the implementation of large images is increasing day by day. Currently, most large image display devices (mainly projectors) use liquid crystals as optical switches. Compared with the CRT projectors of the past, it is small and inexpensive, and the optical system is simple and used. However, it is pointed out that a large amount of light loss occurs because light from the light source is transmitted through the liquid crystal plate to the screen. Therefore, a brighter image can be obtained by reducing light loss by utilizing a micromachine such as an optical modulator element using reflection.

Micromachines are extremely small machines that are difficult to discern with the naked eye. Also known as MEMS (Micro Electro Mechanical System), it can be called microelectromechanical system or device. It is mainly made by applying semiconductor manufacturing technology. It is applied to various information equipment parts such as magnetic and optical heads using micro-optics and limiting devices, and it is also applied to biomedical field and semiconductor manufacturing process using various micro fluid control technologies. Micromachines can be divided into micro-sensors that function as sensing elements, micro-actuators as driving devices, and miniature machines that serve as energy transfer devices.

MEMS is applied to the optical field as one of various application fields. MEMS technology enables the fabrication of optical components smaller than 1mm, enabling ultra-compact optical systems.

Micro-optical components such as optical modulator elements and micro lenses, which are miniature optical systems, have been adopted and applied to communication devices, displays, and recording devices due to advantages such as fast response speed, small loss, and ease of integration and digitization.

The one-dimensional optical modulator element used in the scanning color display device, which is a kind of display, is composed of a driving integrated circuit and a plurality of micro mirrors. One or more micromirrors are gathered to represent one pixel of the projected image.

In this case, in order to express the light intensity of one pixel, the micromirror changes the amount of diffracted light by changing its displacement in proportion to the driving voltage applied from the driving integrated circuit. Here, the driving integrated circuit generates a driving voltage having a specific relationship with respect to the input signal. The amount of diffracted light has a specific nonlinear relationship with the driving voltage.

1 is a graph illustrating a relationship between light intensity versus driving voltage (V) and light intensity versus brightness in a general driving integrated circuit, and FIG. It is a graph showing the relationship between the light intensity versus the driving voltage (V) and the relationship between the light intensity versus the brightness.

The general driving integrated circuit in FIG. 1 is used in an LCD display device. In general driving integrated circuits, the relationship between the light intensity and the driving voltage is in the form of an arccosine function, and thus, the relationship between the light intensity and the brightness is fixed in the form of a linear function as shown in FIG. .

2 shows the relationship between the light intensity versus the driving voltage in the driving integrated circuit in the scanning color display device using the one-dimensional optical modulator element. The relationship between the light intensity and the driving voltage in the driving integrated circuit is in the form of a linear function, and thus the relationship between the light intensity and the brightness is fixed in the form of an arc cosine function as shown in FIG.

That is, there is a limit in expressing an image having an arbitrary luminance characteristic desired by a user because the relationship of brightness to light intensity is fixed.

In the one-dimensional optical modulator device, a plurality of micro mirrors are provided to represent a plurality of pixels. Each micro-mirror has a slightly different difference in the amount of change of displacement with respect to the initial displacement and the driving voltage due to the limitation of the manufacturing. As a result, each micromirror has a problem that the amount of diffracted light is nonuniform with respect to the same driving voltage input.

Accordingly, the present invention provides a scanning color capable of converting the relationship between the amount of light and the input signal into an arbitrary nonlinear relationship by digitally preprocessing the input signal through a linear driving integrated circuit having a light intensity versus drive voltage. A display apparatus, a color image control method, and a color image control recording medium are provided.

In addition, the present invention provides a scanning color display apparatus, a color image control method, and a color image control recording medium which can easily change the luminance characteristic of a projection image represented by a 1D optical modulator device into a gamma curve of a user's preferred form. .

The present invention also provides a scanning color display apparatus, a color image control method, and a color image control recording medium capable of quickly and digitally preprocessing an input signal using a lookup table.

In addition, the present invention provides a scanning color display device, a color image control method for correcting the nonuniformity of the displacement variation according to the initial displacement and the driving voltage of each micromirror to generate diffracted light of uniform brightness for each pixel of the projected image. A color image recording medium is provided.

Other objects of the present invention will be readily understood through the following description.

In order to achieve the above object, according to an aspect of the present invention, a light source; A one-dimensional optical modulator device for generating a modulation beam of a one-dimensional scan line modulating the color light emitted from the light source; A scanner for projecting the modulated beam to a predetermined position on a screen; And receiving an image signal, and converting input light intensity information extracted from the image signal into converted reference light intensity information having a gamma variable adjusted and linearly reduced, and wherein the color light is a 1D optical modulator device according to the reference light intensity information. A scanning color display device may be provided that includes an image control circuit that is modulated to and projected onto the screen through the scanner.

In order to achieve the above objects, according to another aspect of the present invention, there is provided a light source, a one-dimensional optical modulator element for generating a modulated beam of one-dimensional scanning line modulating color light emitted from the light source, and the modulated beam on a screen. A method of controlling an image of a scanning color display device including a scanner projecting at a position, the method comprising: (a) receiving an image signal including input light intensity information on the color light; (b) extracting the input light intensity information from the video signal; (c) converting the input light intensity information into converted reference light intensity information with a gamma variable adjusted and linearly reduced; And (d) causing the one-dimensional optical modulator device to modulate the color light according to the conversion reference light intensity information and to project the color light onto the screen through the scanner.

In the step (c), the input light intensity information is converted from the input light intensity information to the reference light intensity information by a reference table storing a corresponding relationship between the input light intensity information and the reference light intensity information according to the gamma variable. can do.

Preferably, the input light intensity information and the conversion reference light intensity information may be light intensity of each pixel constituting the one-dimensional scan line, respectively.

The one-dimensional optical modulator device may further include a driving integrated circuit configured to generate a driving voltage according to the optical modulator control signal; And a plurality of micro mirrors configured to generate the modulated beams by modulating the beams incident by the displacements changed according to the driving voltage, wherein the micro mirrors may be in charge of one pixel.

Here, the driving voltage may be proportional to the conversion reference light intensity information.

In addition, the micromirror may change its displacement in proportion to the driving voltage.

Preferably, the input light intensity may be converted into reference light intensity information having a gamma variable adjusted, and the reference light intensity information may be converted into the converted reference light intensity information linearly reduced.

이고, I는 상기 변조빔의 밝기, I_o는 상기 변조빔의 평균 밝기, λ는 상기 변조빔의 파장, H는 상기 구동전압에 의한 변위변화량, H_o는 상기 마이크로 미러의 초기 변위이고, +부호는 상기 변조빔이 0차 회절광인 경우이고, -부호는 상기 변조빔이 ±1차 회절광인 경우이다.Here, the relationship between the brightness of the modulated beam and the displacement by the micromirror may be represented by a cosine function. Here, the cosine function

I is the brightness of the modulation beam, I _o is the average brightness of the modulation beam, λ is the wavelength of the modulation beam, H is the amount of displacement change by the driving voltage, H _o is the initial displacement of the micromirror, + The sign is the case where the modulated beam is zero-order diffracted light, and the sign-is the case where the modulated beam is ± first-order diffracted light.

이고, B_std 는 기준 광강도 정보, B_input 은 입력 광강도 정보, N은 상기 기준 광강도 정보의 분해능,

는 상기 감마 변수,

이고, +부호는 상기 변조빔이 0차 회절광인 경우이고, -부호는 상기 변조빔이 ±1차 회절광인 경우이다. The relationship between the reference light intensity information and the input light intensity information may be represented as an inverse function of the cosine function. Here, the inverse function

B _std is reference light intensity information, B _input is input light intensity information, N is resolution of the reference light intensity information,

Is the gamma variable,

Where + is the case where the modulated beam is zero-order diffracted light, and-is the case where the modulated beam is ± first-order diffracted light.

In addition, the relationship between the conversion reference light intensity information and the reference light intensity information matches the minimum and maximum values of the reference light intensity information with the conversion reference light intensity information having the minimum and maximum brightness of the modulation beam for each micromirror. It can be a relationship. That is, the relationship between the conversion reference light intensity information and the reference light intensity information may be based on B _cal = Binoffset [k] + (BinSlope [k] × B _std >> M). Here, B _cal is the conversion reference light intensity information, Binoffset [k] is the conversion reference light intensity at which the modulation beam of the k (natural number) micromirror has the minimum brightness, and BinSlope [k] is the modulation beam of the k th micromirror. The difference between the conversion reference light intensity having the maximum brightness and the conversion reference light intensity having the minimum brightness, B _std is the reference light intensity information and M = log ₂ N (N is the resolution of the reference light intensity information).

Preferably, the image control circuit has a look-up table storing a correspondence between the input light intensity information and the conversion reference light intensity information according to the gamma variable, and the input is determined by the reference table. The conversion from the light intensity information to the reference light intensity information may be performed.

In addition, the resolution of the reference light intensity information may be better than the resolution of the input light intensity information.

And the gamma variable is adjustable.

In order to achieve the above objects, according to another aspect of the present invention, a color image control recording medium having a computer readable and executable code recorded thereon may be provided.

Hereinafter, exemplary embodiments of a scanning color display apparatus, a color image control method, and a color image control recording medium according to the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Numbers (eg, first, second, etc.) used in the description of the present specification are merely identification symbols for sequentially distinguishing identical or similar entities.

3 is a block diagram of a scanning color display device including a 1D optical modulator device according to an exemplary embodiment of the present invention. 4 to 6 are diagrams showing the micro mirror and modulation principle included in the one-dimensional optical modulator device.

Referring to FIG. 3, the scanning color display apparatus includes a light source 110, an illumination optical system 120, a one-dimensional optical modulator element 130, a relay optical system 140, a scanner 150, a projection optical system 160, and a screen ( 170 and an image control circuit 180.

The light source 110 irradiates a beam to project an image onto the screen 170. The light source 110 may emit white light, or may emit any one of three primary colors of red, green, and blue light. Preferably, the light source 110 may be a laser, an LED or a laser diode. When irradiating white light, a color separation unit (not shown) may be provided to separate white light into red light, green light, and blue light according to a predetermined condition.

The illumination optical system 120 reflects the direction of the beam projected from the light source 110 at a predetermined angle so that the beam is concentrated on the one-dimensional optical modulator element 130. When color separation is performed by a color separation unit (not shown), a function of concentrating the beam may be added.

The one-dimensional optical modulator device 130 generates a modulated beam that is diffracted light by modulating the beam irradiated through the illumination optical system 120 according to the optical modulator control signal received from the image control circuit 180. The one-dimensional optical modulator device 130 controls the light intensity corresponding to any one of the vertical scanning lines of the image to be displayed or controls the light intensity corresponding to any one of the horizontal scanning lines.

In the following description, it is assumed that the one-dimensional optical modulator element 130 corresponds to any one of the vertical scan lines in an image forming one frame.

The one-dimensional optical modulator element 130 includes a plurality of micro mirrors.

Referring to FIG. 4, the micromirror 20 includes a substrate 1, an insulating layer 2, a sacrificial layer 3, a ribbon structure 4, and a piezoelectric body 5.

5 (a) and 5 (b) are sectional views showing an enlarged portion A in FIG. When the wavelength of light is λ, the insulating layer on which the ribbon structure 4 and the lower reflecting layer 2a are formed, in which the micromirror 20 is not deformed (no voltage is applied), and the upper reflective layer 4a is formed. The interval between (2) is equal to λ / 2. Thus, the total path difference between the light reflected from the ribbon structure 4 and the insulating layer 2 is equal to λ so that the zeroth order diffracted light (i.e. the reflected light) interferes with constructive interference and the ± first order diffracted light has a destructive interference ( (A) of FIG. 5).

In addition, when a proper voltage is applied to the piezoelectric body 5, the ribbon structure 4 moves toward the insulating layer 2 or vice versa by the pressure generated in the piezoelectric body 5. At this time, the interval between the ribbon structure 4 and the insulating layer 2 on which the lower reflective layer 2a is formed is equal to λ / 4 or 3λ / 4. Therefore, the total path difference between the light reflected from the ribbon structure 4 and the insulating layer 2 is equal to λ / 2 so that the zeroth order diffracted light has a destructive interference and the ± first order diffracted light has a constructive interference (see FIG. b)).

That is, in the case of using the 0th order diffracted light, it has the maximum brightness due to constructive interference when the path difference of the diffracted light is an even multiple of λ / 2, and has the minimum brightness due to the destructive interference when an odd multiple of λ / 2.

In the case of using the ± 1st order diffracted light, when the path difference of the diffracted light is an even multiple of [lambda] / 2, it has a minimum brightness due to the destructive interference, and has a maximum brightness due to constructive interference when an odd multiple of [lambda] / 2.

If necessary, the micromirror 20 uses zero-order diffraction light or ± first-order diffraction light, and the principle of interference is as described above. By using the result of such interference, the micromirror 20 may load the signal to the light by adjusting the amount of light of the incident beam. A portion of the sacrificial layer 3 is here used to support the ribbon structure 4 without being etched.

The micromirror 20 illustrated in FIG. 4 is responsible for any one pixel among a plurality of pixels constituting the vertical scanning line to adjust gray scale, that is, light intensity.

Referring to FIG. 6, a plurality of micromirrors 20-1, 20-2,..., 20-m illustrated in FIG. 4, which is one pixel, are gathered together (here m (natural numbers)) to form a one-dimensional optical modulator. The element 130 is formed. The one-dimensional optical modulator element 130 is a diffracted light having a plurality of micro mirrors (20-1, 20-2, ..., 20-m) gathered in parallel to have a different signal size for a constant incident beam by the interference principle, As a device capable of generating a modulated beam and carrying a signal on light, a device that is in charge of a vertical scanning line, which is a one-dimensional image line, as described above, is generally referred to.

Hereinafter, the one-dimensional optical modulator device 130 will be described as being in charge of a vertical scan line, that is, a one-dimensional image line, composed of m pixels (where m is a natural number).

The one-dimensional optical modulator device 130 is configured to generate a driving voltage for each pixel according to the light intensity information of each pixel constituting the vertical scan line included in the optical modulator control signal. Therefore, a plurality of micro mirrors 20-1, 20-2, ..., 20-m are used to generate modulated beams of light diffracted light whose modulated light intensity is modulated using the interference or diffraction principle of light.

Preferably, the plurality of micro mirrors 20-1, 20-2, ..., 20-m is equal to the number of pixels constituting the vertical scanning line. The modulated diffracted light is light in which image information (ie, light intensity information) of a vertical scan line to be projected on the screen 170 is reflected later. Here, the diffracted light may be zero-order diffraction light or ± first-order diffraction light. The relay optical system 140 may transmit the modulated beam generated by the one-dimensional optical modulator element 130 to the scanner 150. One or more lenses may be included, and the modulation beam is adjusted as necessary to match the size of the one-dimensional optical modulator device 130 and the size of the scanner 150 to deliver the modulated beam.

The scanner 150 reflects the modulated beam incident through the relay optical system 140 at a predetermined angle and projects it onto the screen 170. In this case, the predetermined angle is determined by the scanner control signal received from the image control circuit 180. The scanner control signal rotates the scanner 150 at an angle at which the modulation beam can be projected at the position of the vertical scan line on the screen 170 corresponding to the optical modulator control signal in synchronization with the optical modulator control signal.

The scanner 150 may be a galvanometer scanner or a polygon mirror scanner. The galvano scanner has a rectangular plank shape and a mirror is attached to one side. It rotates left and right within a predetermined angle range about an axis, and in the present invention, the image is projected on the screen 170 by changing the reflection angle of the incident light when rotating in either the left or right direction or left and right directions. Polygon mirror scanners have the shape of a polygonal column with mirrors attached to the sides of the polygonal column. The mirrors attached to each side surface rotate in one direction about the axis to change the reflection angle of the light incident by the rotation to project an image on the screen 170.

The projection optics 160 allow the modulation beams reflected by the scanner 150 to be projected onto the screen 170. Projection lens (not shown).

The image control circuit 180 receives an image signal corresponding to one frame and controls the 1D optical modulator element 130 and the scanner 150 according to the image signal.

The image control circuit 180 transmits the light intensity information (that is, the light intensity) of each pixel constituting the frame to the one-dimensional optical modulator element 130 and the optical modulator control signal transmitted to the one-dimensional optical modulator element 130. Correspondingly, the rotation angle of the scanner 150 is adjusted so that the vertical scan line is properly projected on the screen 170. In the present invention, when the plurality of vertical scan lines corresponding to one frame are all the same, the scanner 150 may be rotated at a predetermined angular velocity.

Here, the image control circuit 180 extracts input light intensity information from the image signal. The input light intensity information is converted into conversion reference light intensity information according to a conversion method to be described later, and an optical modulator control signal corresponding to the conversion reference light intensity information is generated and transmitted to the one-dimensional optical modulator element 130.

In the present invention, the one-dimensional optical modulator device 130 includes a driving integrated circuit and a plurality of micro mirrors 20. The driving integrated circuit generates a plurality of driving voltages for changing displacements of the plurality of micromirrors 20 according to the optical modulator control signals applied from the image control circuit 180, and transmits the plurality of driving voltages to the micromirrors 20. Here, the optical modulator control signal includes conversion reference light intensity information.

7 is a flowchart of a color image control method according to an exemplary embodiment of the present invention, and FIG. 8 is a flowchart of a method of forming a conversion formula or reference table for color image control according to the present invention. 9 is a graph showing the relationship between the driving voltage (V), the displacement (H) and the brightness (I) of the micromirror 20 in the one-dimensional optical modulator element 130, Figure 10 is a one-dimensional optical modulator element before correction In FIG. 130, it is a graph showing the relationship between the input light intensity information B _input , the displacement H of the micromirror 20, and the brightness I.

Referring to FIG. 7, a color image control method according to an exemplary embodiment of the present invention is as follows.

In operation S710, the image control circuit 180 receives an image signal including input light intensity information.

In step S720, input light intensity information is extracted from the video signal.

In step S730, the input light intensity information is converted into conversion reference light intensity information.

In operation S740, the conversion reference light intensity information is applied to the one-dimensional optical modulator element 130, and accordingly, the one-dimensional optical modulator 130 modulates the incident color light to generate a modulated beam that is diffracted light. 150 to project onto the screen 170.

In this case, a method for obtaining a conversion equation or a reference table for converting input light intensity information into conversion reference light intensity information in step S730 is illustrated in FIGS. 8 to 10.

Referring to FIG. 8, in step S810, reference light corresponding to the maximum brightness and the minimum brightness of all the micromirrors 20-1, 20-2,..., 20-m included in the one-dimensional optical modulator element 130. The range of the driving voltage is adjusted so that the maximum luminance reference light intensity and the minimum luminance reference light intensity, which are intensity information, exist between 0 and N-1. Here, when the reference light intensity information has a resolution of M bits, N is ^2M .

Referring to the left graph of FIG. 9, the displacement H and the driving voltage V of the micromirror 20 are proportional to each other in relation to the linear function. That is, the equation (710) of H = KV is satisfied. That is, when the driving voltage V applied to both piezoelectric elements 15 of the micromirror 20 increases, the vertical displacement of the micromirror 20 also increases in proportion.

9, it can be seen that the displacements H of the plurality of micromirrors 20 and the brightness I of the modulated beam are in a relationship between cosine functions 720a and 720b.

The cosine function is shown in Equation 1 below.

Where I is the brightness of the modulation beam, I _o is the average brightness of the modulation beam (i.e. 1/2 of the maximum value), λ is the wavelength of the modulation beam, H is the displacement variation of the micromirror 20 due to the driving voltage, H _o is the initial displacement of the micromirror 20. -Is the case where the modulated beam is zero-order diffracted light, and + is the case where the modulated beam is ± first-order diffracted light.

As shown in FIG. 4, the micromirror 20 is spaced apart from the upper reflective layer 4a and the lower reflective layer 2a by a predetermined interval during initial fabrication. This gap is H _{o which} is the initial displacement of the micromirror 20. Thereafter, when the driving voltage is applied, the micromirror 20 changes the displacement in the upward or downward direction, and the change amount of the displacement is referred to as H. Here, H has a positive value when the change in the upward direction and a negative value when the change in the downward direction.

The reflected beam from the upper reflection layer (4a) and the spacing between the lower reflection layer (2a) is a H + H _o, the beam and the lower reflection layer (2a) reflected by the upper reflection layer (4a) according to the displacement variation of a micro mirror (20) The path difference between them becomes 2 × (H + H _o ).

Therefore, when the modulated beam to be used is zero-order diffracted light, the brightness when the path difference is an odd multiple of λ / 2 becomes maximum (that is, Imax), and the brightness when the path difference is an even multiple of λ / 2 is minimum (that is, , Imin = 0). Alternatively, when the modulated beam to be used is ± 1st order diffracted light, the brightness when the path difference is an even multiple of λ / 2 becomes maximum (that is, Imax), and the brightness when the path difference is an odd multiple of λ / 2 is minimum (that is, , Imin = 0).

According to the graph shown in FIG. 9, the relationship between the driving voltage and the displacement of the micromirror 20 has a linear (ie, linear function) relationship, and the relationship between the displacement of the micromirror 20 and the brightness of the modulation beam. Has a relation of a sine wave cosine function as shown in Equation 1 above. Therefore, when the correlation is connected, the relationship between the driving voltage V and the brightness I of the modulation beam has a sinusoidal cosine function.

Here, the reference light intensity information input from the image control circuit 180 to the driving integrated circuit of the one-dimensional optical modulator element 130 includes reference light intensity for making the color light of the light source 110 have various brightnesses.

When the driving integrated circuit is designed such that the relationship between the light intensity versus the driving voltage included in the light intensity information has a linear function, as shown in FIG. 2A, the light intensity versus modulation included in the light intensity information The brightness of the beam has a relationship as shown in FIG. The image control circuit 180 includes the light intensity that has been digitally preprocessed in the light intensity information and transmits the light intensity information to the one-dimensional optical modulator device 130 to have an arbitrary luminance characteristic.

The luminance characteristic of the input light intensity information included in the image signal is generally expressed by Equation 2 below.

는 휘도 특성인 감마 변수를 의미한다. Where I is the brightness of the modulation beam, B _input is the input light intensity information,

Denotes a gamma variable that is a luminance characteristic.

을 변화시킴에 따라 입력 광강도 정보(B_input)과 변조빔의 밝기(I) 간의 관계는 다양해지며, 상기 수학식 2의 관계를 만족시키도록 한다면 임의의 휘도 특성을 가지는 투사 영상을 얻을 수 있게 된다. Gamma variable

The relation between the input light intensity information (B _input ) and the brightness (I) of the modulation beam is varied according to the change of. If the relation of Equation 2 is satisfied, a projection image having an arbitrary luminance characteristic can be obtained. do.

The image control circuit 180 converts input light intensity information extracted from the image signal into reference light intensity information. The reference light intensity information refers to light intensity information, that is, reference light intensity, which is used as an input of a driving integrated circuit having a characteristic of a primary function to obtain a linear driving voltage. The reference light intensity is a value whose relationship with the driving voltage is predetermined so that a specific driving voltage is obtained when fabricating the driving integrated circuit. In the present invention, there is a relationship between the primary functions.

)가 반영될 수 있도록 한다. Therefore, the input light intensity information extracted from the video signal is converted into reference light intensity information for applying to the driving integrated circuit. For these transformations, any gamma variable you want (

) Can be reflected.

The relationship between the input light intensity information extracted from the image signal and the reference light intensity information included in the optical modulator control signal for applying to the driving integrated circuit is expressed by Equation 3 below.

는 감마 변수,

을 의미한다. +는 스캐닝 컬러 디스플레이 장치에서 이용하는 변조빔이 0차 회절광인 경우이고, -는 ±1차 회절광인 경우이다. This is a combination of Equations 1 and 2, where B _std is reference light intensity information, B _input is input light intensity information, N is resolution of reference light intensity information,

Is the gamma variable,

Means. + Is the case where the modulated beam used in the scanning color display device is 0th order diffracted light, and − is the case where ± 1st order diffraction light is used.

The resolution of the reference light intensity information generally means the degree of division between the darkest value and the brightest value. The resolution of the reference light intensity information is preferably higher than the resolution of the input light intensity information. For example, if the input light intensity information has a resolution of ⁸ bits, that is, 256 (= 2 ⁸ ), it is possible to distinguish from 0 to 255, and the reference light intensity information is 10 bits, that is, 0 to 1023. It can have a resolution of 1024 (= 2 ¹⁰ ) that can be distinguished up to. This is because the resolution of the reference light intensity information must be higher than the resolution of the input light intensity information in order to maintain the accuracy of the driving voltage output from the driving integrated circuit of the 1D optical modulator device 130. This will be described in detail with reference to FIG. 11 to be described later.

In Equation 1, the relationship between the driving voltage V and the brightness I of the modulation beam has a cosine function, and in Equation 2, the brightness I and the input light intensity information B _input of the modulation beam are an exponential function. Has a relationship with In addition, since the driving voltage V and the reference light intensity information B _std have a linear function relationship due to the linear characteristics of the driving integrated circuit, the input light intensity information B _input and the reference light intensity information shown in Equation 3 above are used. The relationship between (B _std ) holds.

When the above equation (3) is summarized with respect to the reference light intensity information (B _std ), the relationship as shown in the following equation (4) is established.

Here, + is a case where the modulation beam used in the scanning color display device is 0th order diffracted light, and − is a case where ± 1st order diffraction light is used.

Accordingly, the input light intensity information may be converted into reference light intensity information so as to have a relation as shown in Equation 4, and then the reference light intensity information may be loaded on the optical modulator control signal and transmitted to the one-dimensional optical modulator element 130. .

Since the conversion of the input light intensity information and the reference light intensity information is as defined in Equation 4, the image control circuit 180 is configured to convert the input light intensity information and the reference light intensity information in the form of a lookup table. The transformation relationship may be stored in advance. When stored in the form of a reference table, the reference light intensity information may be quickly searched and converted in response to the input light intensity information, and the preprocessing operation in the image control circuit 180 may be omitted, thereby increasing the reaction speed.

In the present invention, when the relationship between the brightness I of the modulation beam and the input light intensity information B _input is defined in addition to the exponential function as shown in Equation 2, the relation of other function types is defined. Therefore, the projection image having various luminance characteristics can be represented.

However, due to the limitations of product manufacturing for each micromirror 20, the initial displacement H _o of the micromirror 20 and the displacement change amount H according to the driving voltage are shown in each of the micromirrors 20 as shown in 720a and 720b. There is a slight difference.

That is, the displacement of the first micromirror 20 by Hmin (a) is changed by the driving voltage having the value of Vmin (a), and the brightness of the diffracted light at this time becomes Imin (a), that is, zero. Then, the displacement is changed by Hmax (a) by the driving voltage having the value of Vmax (a), and the brightness of the diffracted light at this time becomes Imax (a).

However, the displacement of the second micromirror 20 by Hmin (b) is changed by the driving voltage having the value of Vmin (b), and the brightness of the diffracted light at this time becomes Imin (b), that is, zero. The displacement is changed by Hmax (b) by the drive voltage having the value of Vmax (b), and the brightness of the diffracted light at this time becomes Imax (b).

In the driving integrated circuit of the one-dimensional optical modulator device 130, since the relationship between the input light intensity information and the generated driving voltage has a first function relationship as shown in FIG. 2A, the input light intensity information ( The relationship between B _input , the displacement H of the micromirror 20, and the brightness I is as shown in FIG. 8. Here, the input light intensity information (Binput) is an example that has a resolution of 8 bits (bit), but is not limited thereto. In the absence of correction, among the m (natural numbers) micromirrors 20 shown in FIG. 6, minimum and maximum luminance input light intensity information which has minimum and maximum brightness in the K-th micromirror are obtained by using BinMax [K], BinMin [ K]. The minimum and maximum luminance input light intensity information for the minimum and maximum brightness in the L-th micromirror are referred to as BinMax [L] and BinMin [L]. Here, K and L are natural numbers of m or less (refer FIG. 10).

That is, in step S810, the driving voltage is adjusted so that the values of BinMax [K], BinMin [K], BinMax [L], and BinMin [L] are between 0 and N-1 (= 2 ^M -1), The driving voltage at this time is called a correction driving voltage.

In step S820, the maximum luminance reference light intensity and the minimum luminance reference light intensity of each micromirror 20 are respectively measured under the correction driving voltage.

In operation S830, a first conversion equation for matching the maximum luminance reference light intensity to the maximum reference light intensity (ie, N-1) and matching the minimum luminance reference light intensity to the minimum reference light intensity (ie, 0) is obtained.

This is because the reference light intensity above the maximum brightness reference light intensity indicates the brightness lower than the maximum brightness, so an error occurs in the brightness according to the light intensity information. In addition, since the reference light intensity below the minimum brightness reference light intensity indicates a brightness higher than the minimum brightness, an error occurs in brightness according to the light intensity information.

Therefore, in order to correct this, the reference light intensity is arranged within the minimum luminance reference light intensity and the maximum luminance reference light intensity using Equation 5 (ie, the first conversion equation).

B _cal = Binoffset [k] + (BinSlope [k] × B _std >> M)

Where B _cal is conversion reference light intensity information, Binoffset [k] is the minimum luminance reference light intensity of the k th micromirror, BinSlope [k] is the difference between the maximum luminance reference light intensity and the minimum luminance light intensity of the k th micromirror, B _std is reference light intensity information, M = log ₂ N (N is resolution of reference light intensity information).

In order to obtain the actual conversion reference light intensity information, when the reference light intensity information is x as an independent variable and the conversion reference light intensity information is y as a dependent variable, it is in the form of a linear function of y = ax + b. In this case, in the k-th micromirror, (reference light intensity information, converted light intensity information) is (0, the minimum luminance reference light intensity Binoffset [k]), (N-1, the maximum luminance reference light intensity BinMax [k]) It becomes the linear function passing two points. Since the slope of the linear function is (BinMax [k]-Binoffset [k]) / N and is a float, it takes a long time to calculate it. In addition, since the conversion reference light intensity information Bstd needs only an integer value, there is no need to perform a real number operation.

Therefore, bit shifting by performing int operation enables operation in a much shorter time. To do this, multiply BinSlope [k] (= BinMax [k] -Binoffset [k]) by the reference light intensity information B _std , bit shift by M (= log2N), and then add Binoffset [k] to match the converted reference light intensity information. You get B _cal .

Here, the conversion from the reference light intensity information to the conversion reference light intensity information is referred to as linear reduction.

In operation S840, a second conversion equation for converting the input light intensity into a reference light intensity according to the gamma variable is obtained. The second conversion equation is based on Equation 4 described above. The gamma variable is set to reflect the luminance characteristic desired by the user in the input light intensity information included in the image signal and is matched with the reference light intensity information.

In step S850, the input light intensity information is converted into the reference light intensity information by the second conversion equation (Equation 4), and the reference light intensity information is converted back into the conversion reference light intensity information by the first conversion equation (Equation 5). Convert. For each micromirror, the conversion reference light intensity information according to the input light intensity information is formed in the form of a reference table.

Subsequently, the conversion of the input light intensity information to the converted light intensity information can be quickly performed based on the reference table. When the input light intensity information of each pixel (ie, each micro mirror) is 0, the minimum luminance When the input light intensity information is 255 (e.g., when the input light intensity information has 8 bits of resolution), the maximum luminance is shown.

11 is a graph illustrating a conversion relationship in which various gamma variables are reflected between input light intensity information and reference light intensity information according to an exemplary embodiment of the present invention. In this example, it is assumed that the input light intensity information has a resolution of 8 bits (= 256), and the reference light intensity information has a resolution of 10 bits (= 1024), but it is only one embodiment and may have a different resolution. Of course. It is advantageous for the reference light intensity information to have a higher resolution than the input light intensity information to increase the accuracy of the driving voltage output from the driving integrated circuit of the one-dimensional optical modulator element 130.

Corresponding graphs 1110, 1120, 1130, and 1140 between reference light intensity information to which gamma variables 1.2, 1.5, 1.8, and 2.0 are applied and input light intensity information according to Equation 4 described above. The input light intensity information included in the image signal is converted into reference light intensity information according to one of the corresponding graphs, and applied to the one-dimensional optical modulator device 130 to express a color image having a desired luminance characteristic. .

12 is a diagram illustrating a brightness curve of a modulation beam compared to input light intensity information according to the present invention. Here, the driving integrated circuit has a linear gray scale voltage characteristic that outputs a driving voltage in proportion to the reference light intensity information included in the applied optical modulator control signal.

Referring to FIG. 12, three brightnesses of a modulation beam according to input light intensity information are illustrated. When not pretreated according to the present invention will have a curve 1210 of the same arc cosine shape as shown in Figure 2 (b). If the gamma variable is set to 1, it has a parabolic curve 1220 similar to a quadratic function. In the case where the gamma variable is set to 2.2, the input light intensity information and the brightness of the modulation beam have a linear function 1230 having a linear function, indicating the most optimal luminance characteristic. In addition, by varying the gamma variable, it is possible to have a brightness curve of the modulation beam compared to various types of input light intensity information.

In the present invention, the image control circuit 180 includes a method of converting the above-described input light intensity information into reference light intensity information, and generates an optical modulator control signal and a scanner control signal to generate the one-dimensional optical modulator element 130 and the scanner. It may include a recording medium on which a computer readable and executable code is recorded, which carries out the method for controlling 150.

As described above, the scanning color display apparatus, the color image control method, and the color image control recording medium according to the present invention perform a digital preprocessing operation on an input signal through a driving integrated circuit having a linear configuration of driving voltage versus light intensity. As a result, the relationship between the amount of light and the input signal can be converted into an arbitrary nonlinear relationship.

In addition, it is possible to easily change the luminance characteristic of the projection image represented by the one-dimensional optical modulator element to a gamma curve of a user's preferred form.

In addition, a lookup table may be used to quickly preprocess the input signal digitally.

In addition, the non-uniformity of the displacement variation according to the initial displacement and the driving voltage of each micromirror may be corrected so that each pixel of the projected image generates diffracted light of uniform brightness. As a result, there is an effect of eliminating the unevenness of brightness in the vertical direction of the projection image generated without correction and improving image quality.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention as set forth in the claims below It will be appreciated that modifications and variations can be made.

Claims (26)

Light source; A one-dimensional optical modulator device for generating a modulation beam of a one-dimensional scan line modulating the color light emitted from the light source; A scanner for projecting the modulated beam to a predetermined position on a screen; And Receiving an image signal, and converting input light intensity information extracted from the image signal into converted reference light intensity information having a gamma variable adjusted and linearly reduced, wherein the color light is a one-dimensional optical modulator device according to the converted reference light intensity information. Control circuitry that is modulated to and projected onto the screen through the scanner Scanning color display device comprising a. The method of claim 1, And the input light intensity information and the conversion reference light intensity information are light intensities of respective pixels constituting the one-dimensional scan line, respectively. The method of claim 2, The one-dimensional optical modulator device, A driving integrated circuit generating a driving voltage according to the optical modulator control signal; And It includes a plurality of micro mirrors for generating the modulated beam by modulating the incident beam by the displacement that is changed according to the drive voltage, And each of the micro mirrors is in charge of one pixel. The method of claim 3, And the driving voltage is proportional to the conversion reference light intensity information. The method of claim 4, wherein And the displacement of the micro mirror is changed in proportion to the driving voltage. The method of claim 5, And the input light intensity is converted into reference light intensity information with a gamma variable adjusted, and the reference light intensity information is converted into the converted reference light intensity information for correcting nonuniformity for each pixel. The method of claim 6, And a relationship between the brightness of the modulated beam and the displacement caused by the micromirror is represented by a cosine function. Where the cosine function

I is the brightness of the modulation beam, I _o is the average brightness of the modulation beam, λ is the wavelength of the modulation beam, H is the amount of displacement change by the driving voltage, H _o is the initial displacement of the micromirror, + The sign is the case where the modulated beam is zero-order diffracted light, and the sign is the case where the modulated beam is ± first-order diffracted light. The method of claim 7, wherein And the relationship between the reference light intensity information and the input light intensity information is represented by an inverse function of the cosine function. Where the inverse is

B _std is reference light intensity information, B _input is input light intensity information, N is resolution of the reference light intensity information,

Is the gamma variable,

Where + is the case where the modulation beam is 0th order diffracted light, and + is the case where the modulation beam is ± 1st order diffraction light. The method of claim 8, The relationship between the conversion reference light intensity information and the reference light intensity information is to match the minimum and maximum values of the reference light intensity information to the conversion reference light intensity information having the minimum and maximum brightness of the modulation beam for each micromirror. Scanning color display device characterized in that. The method of claim 9, And the relationship between the converted reference light intensity information and the reference light intensity information is according to B _cal = Binoffset [k] + (BinSlope [k] × B _std >> M). Where B _cal is the conversion reference light intensity information, Binoffset [k] is the conversion reference light intensity at which the modulation beam of the k-th micromirror has the minimum brightness, and BinSlope [k] is the modulation beam of the k-th micromirror. The difference between the conversion reference light intensity having the maximum brightness and the conversion reference light intensity having the minimum brightness, B _std is the reference light intensity information, and M = log ₂ N (N is the resolution of the reference light intensity information). The method of claim 1, The image control circuit has a look up table storing a correspondence between the input light intensity information according to the gamma variable and the conversion reference light intensity information, and from the input light intensity information according to the reference table. And a conversion to the conversion reference light intensity information. The method of claim 6, And the resolution of the reference light intensity information is better than the resolution of the input light intensity information. The method of claim 1, And the gamma parameter is adjustable. An image of a scanning color display device including a light source, a one-dimensional optical modulator element for generating a modulated beam of one-dimensional scan line modulated with color light emitted from the light source, and a scanner for projecting the modulated beam to a predetermined position on a screen; In the control method, (a) receiving an image signal including input light intensity information on the color light; (b) extracting the input light intensity information from the video signal; (c) converting the input light intensity information into converted reference light intensity information with a gamma variable adjusted and linearly reduced; And (d) causing the one-dimensional optical modulator element to modulate the color light according to the conversion reference light intensity information and to project it onto the screen through the scanner Color image control method comprising a. The method of claim 14, And the input light intensity information and the conversion reference light intensity information are light intensities of respective pixels constituting the one-dimensional scan line, respectively. The method of claim 15, The one-dimensional optical modulator device, A driving integrated circuit generating a driving voltage according to the optical modulator control signal; And A plurality of micro mirrors for generating the modulated beam by modulating the incident beam by the displacement that changes according to the drive voltage Color image control method comprising a. The method of claim 16, And the driving voltage is proportional to the conversion reference light intensity information. The method of claim 17, And the displacement of the micro mirror is changed in proportion to the driving voltage. The method of claim 18, The relationship between the brightness of the modulation beam and the displacement by the micro mirror is represented by a cosine (cosine) function. Where the cosine function

I is the brightness of the modulation beam, I _o is the average brightness of the modulation beam, λ is the wavelength of the modulation beam, H is the amount of displacement change by the driving voltage, H _o is the initial displacement of the micromirror, + The sign is the case where the modulated beam is zero-order diffracted light, and the sign is the case where the modulated beam is ± first-order diffracted light. The method of claim 19, Step (c) is, (c1) converting the input light intensity information into reference light intensity information whose gamma parameter is adjusted; And (c2) converting the reference light intensity information into the conversion reference light intensity information correcting the nonuniformity for each pixel, And the relationship between the reference light intensity information and the input light intensity information is represented by an inverse function of the cosine function. Where the inverse is

B _std is reference light intensity information, B _input is input light intensity information, N is resolution of the reference light intensity information,

Is the gamma variable,

Where + is the case where the modulation beam is 0th order diffracted light, and + is the case where the modulation beam is ± 1st order diffraction light. The method of claim 20, The relationship between the conversion reference light intensity information and the reference light intensity information is to match the minimum and maximum values of the reference light intensity information to the conversion reference light intensity information having the minimum and maximum brightness of the modulation beam for each micromirror. Color image control method characterized in that. The method of claim 21, And the relationship between the converted reference light intensity information and the reference light intensity information is based on B _cal = Binoffset [k] + (BinSlope [k] × B _std >> M). Where B _cal is the conversion reference light intensity information, Binoffset [k] is the conversion reference light intensity at which the modulation beam of the k (micron) micromirror has the minimum brightness, and BinSlope [k] is the modulation beam of the k th micromirror. The difference between the conversion reference light intensity having the maximum brightness and the conversion reference light intensity having the minimum brightness, B _std is the reference light intensity information, and M = log ₂ N (N is the resolution of the reference light intensity information). The method of claim 14, In the step (c), the input light intensity information is converted from the input light intensity information to the conversion reference light intensity information by a reference table storing a correspondence relationship between the input light intensity information and the conversion reference light intensity information. Color image control method. The method of claim 20, And the resolution of the reference light intensity information is higher than the resolution of the input light intensity information. The method of claim 14, And the gamma variable is adjustable. A color image control recording medium having recorded thereon a computer readable and executable code for performing the color image control method according to any one of claims 14 to 25.

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